After the egg was obtained and then auto-consumed, the first turtle collection achievements unlock along with you also getting a mail to go see Rota in Arborstone.
Rota isn't at Arborstone, the game also failed to tag the egg as obtained from the DE meta event after completion.
Rota's tag can actually be seen on the map and it's not like she's invisible or anything like that she's not even standing there.
Also, multiple uses of the egg doesn't work. You can see the images here https://imgur.com/a/dZJu3dd